Lately, with development of high-speed, large-capacity wireless communication schemes represented by Long Term Evolution (LTE), a need for modulation signals having a great Peak to Average Power Ratio (PAPR) are increasing. Generally, in an amplifier for wireless communication, signals having a great PAPR require high consumption power, and cause deterioration of operation efficiency. In order to overcome the problems, a Doherty amplifier capable of performing high-efficient operations over a wide output range is used.
The Doherty amplifier generally includes a carrier amp and a peak amp. The carrier amp amplifies signals unconditionally, whereas the peak amp amplifies signals having higher power than specific power.